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Fast‐atom‐bombardment mass spectrometry and 1 H‐NMR spectrometry in studies of the transformations of thiamine in strongly basic solutions
Author(s) -
Horman Ian
Publication year - 1984
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19840670609
Subject(s) - chemistry , fast atom bombardment , thiamine , mass spectrometry , mass spectrum , nmr spectra database , atom (system on chip) , analytical chemistry (journal) , base (topology) , spectral line , nuclear magnetic resonance spectroscopy , chromatography , organic chemistry , mathematical analysis , physics , mathematics , astronomy , computer science , embedded system
Fast‐atom‐bombardment (FAB) mass spectra have been used to establish or confirm the nature of the yellow‐product and open‐chain forms of thiamine produced in the presence of excess (5 mol‐equivb.) of strong base. Time‐dependent changes in 1 H‐NMR spectra show that the rates of disappearance of the yellow form and of formation of the open‐chain form are the same at pH 12.5, having a pseudo‐first‐order rate constant of k = 2.2 × 10 −3 sec −1 . The implications of these results are discussed in the light of current ideas on the acid‐base dependence of thiamine structures.